Flex pipe debate install locations

[Skullzaflare]

Both the 86 and two 87's I picked up didn't have either style joint. I asked the 2 exhaust shops that sponsor our outlaw karts about their thoughts on adding a flex pipe on the starquests and they both said not to do it unless its a last resort. The flex pipe is designed more or less for front wheel drives where the engine rocks back and forth and need that movement in the exhaust. They both did recommend the other joint that was mentioned if you had a spendy exhaust and were worried about it being damaged. Another valid point one of them made was that if your engine is moving enough to the point where you need to install a flex pipe you have some serious issues like bad motor mounts, trams mounts, and other possible parts. I think I'll be picking up one of the funk lock engine mounts like someone else mentioned so I don't have to ever worry about that problem.

you must have owned some of the cars teenagers have butchered,

if you have solid motor/trans mounts, and solid mounts on the exhaust, you still need a flex spot somewhere to move from body flex.

the ignorance of your local exhaust shop is astonishing yet not surprising. it does not matter the cost of your exhaust, flex or not it will not damage the exhaust, it will only crack your turbo manifold, and help pull on the studs in the head. guess they dont use oil filters in their engines either, as long as you put clean oil in, it should be fine right?

[Trouble_07]

Not too sure how intelligent all you guys are on the subject, but speaking from experience... I worked at an oil change shop for 2 years and was under at minimum 30 cars a day, graduated from a 2 year auto tech program at the top of my class as well as a 1 year auto body program from the same institution. I now work at a renowned upholstery shop where I see at least 2 cars a day. Yes I do own one car that was completely butchered by teenagers and well that's the only one that had a section to allow movement and separate the exhaust system. The other 2 cars were completely factory and neither of them had anything like mentioned. As for the info from my friends at the exhaust shops both of them were from the owners who have been in business for 20+ years and are very well recommended, so I doubt they would feed me a line of bull. But hey everyone is entitled to their own opinion and if it's your car do what you want with it no one can stop you.

[JohnnyWadd]

Not too sure how intelligent all you guys are on the subject, but speaking from experience... I worked at an oil change shop for 2 years and was under at minimum 30 cars a day, graduated from a 2 year auto tech program at the top of my class as well as a 1 year auto body program from the same institution. I now work at a renowned upholstery shop where I see at least 2 cars a day. Yes I do own one car that was completely butchered by teenagers and well that's the only one that had a section to allow movement and separate the exhaust system. The other 2 cars were completely factory and neither of them had anything like mentioned. As for the info from my friends at the exhaust shops both of them were from the owners who have been in business for 20+ years and are very well recommended, so I doubt they would feed me a line of bull. But hey everyone is entitled to their own opinion and if it's your car do what you want with it no one can stop you.

 

Great input!! I was hoping to learn about where you worked and where you went to school. Awesome job opening your reply with a question about our intelligence. Did your school teach you anything about tact or effective communication? Never mind the actual topic of where the best place to install a flex section would be. I am curious how you where under 30 cars a day minimum. I am guessing one of those fast lube places? How did you have time to really look at exhaust systems cranking out cars like that? I have been under a lot of cars but usually under them for something like a half hour or more doing u joints or other similar work. But really that's awesome you can bust out over 30 cars a day. Good job.

 

If all you are going to say is that no flex is needed because you do 30 cars a day and because an exhaust shop told you so. And then you add in...

it's your car do what you want with it no one can stop you.

 

..then let me ask you; why are you even in this thread mucking it up with your off topic responses?

[patra_is_here]

I assume you are more concerned with the engine moving axially (from the TQ of the drivetrain) rather than tipping front to back

 

so that basically makes the pass side mount the fulcrum, so mount flex joint near vertical and as close to the fulcrum as possible. the further away you mount it from the fulcrum, any distance the engine moves will essentially be exaggerated forcing the joint to flex more.

 

visualize looking at the motor head-on, and think about the pivot point of the pass mount, and imagine the bending force being applied to the downpipe.

 

with the stock set-up, the engine movement creates a twist and a bend at the stock flexy joint. since the new style flex joints aren't made for twist, you have to move the flex joint to a vertical orientation.

[Tim_C.]

Its more about absorbing shock from the road than it is engine movement from torque. Both are a factor though.

It needs to be horizontal to help keep the shock from getting to the exhaust manifold studs. A verticle one doesn't help up and down movement as well, which is what both road and motor twist need.

A flex is only part of the equation too. The pipe needs properly supported all the way back, with the first link no further back than the factory hanger at the second cat location. Otherwise, whatever flex is there, won't help much.

I like them horizontally myself so then you can put a nice hi-flow downpipe to get that exhaust evacuating faster from the start. Then you can put a larger flex after. It isn't so convenient to put a 3" flex verticle and just after the turbo connection.